Проведен теоретический анализ имеющихся экспериментальных данных по упругому и неупругому рассеянию \(\alpha+^{13}\) С в области энергий до 90 МэВ. Получены параметры полумикроскопического потенциала в рамках дисперсионной оптической модели (SMDOM). Найденные потенциалы использованы при анализе в рамках метода искаженных волн недавно измеренных нами данных по неупругому рассеянию при энергиях 65 и 90 МэВ. Экспериментальные данные для состояний 3.68 и 7.55 МэВ представлены впервые. Состояния 3.68 и 7.55 МэВ рассмотрены в предположении принадлежности вращательной полосе основного состояния в рамках стандартной вращательной модели. Получено удовлетворительное описание угловых распределений, и определены значения длин деформации. Для остальных возбуждений до энергий 11 МэВ использован моделируемый феноменологический формфактор. Проведенный анализ подтвердил наличие нейтронного гало в состоянии 3.09 МэВ. Сходство формы полученных неупругих формфакторов для состояний 8.86, 10.996 и 11.08 МэВ, а также близость их радиусов дают основание полагать, что ядро \({}^{13}\) C во всех трех состояниях имеет увеличенные размеры и схожую структуру. Сравнение радиальных зависимостей формфакторов для состояний 9.90 и 8.86 МэВ показывает, что волновая функция состояния 9.90 МэВ имеет существенно меньшую пространственную протяженность. Полученные результаты согласуются с величинами радиусов обсуждаемых состояний, определенными в рамках Модифицированной дифракционной модели.

Исследована роль замкнутых и деформированных протонных и нейтронных оболочек в делении ядер \({}^{248}\) Cf и \({}^{254,256}\) Fm с энергией возбуждения от 40 до 56 МэВ. Массово-энергетические распределения осколков деления этих ядер, образованных в реакциях \({}^{16}\textrm{O}+^{232}\) Th и \({}^{16,18}\textrm{O}+^{238}\) U, были измерены при энергиях налетающих ионов вблизи кулоновского барьера с помощью времяпролетного спектрометра CORSET. Показано, что во всех исследованных реакциях повышенный выход осколков в районе массы 100 а.е.м. связан с влиянием деформированной протонной оболочки \(Z\sim 38\) . Обнаружено проявление SuperShort-моды в делении \({}^{256}\) Fm при энергии возбуждения составного ядра 40 МэВ.

The characteristics of heavy ion tracks in phosphate glasses after irradiation under various temperature conditions are presented. Calibration experiments are performed to obtain the dependence of the parameters of the etched tracks on the sample heating temperature and time and on the moment of heating a sample in relation to irradiation and etching. To effectively identify the ion charges, the stability of reproducing the optimum chemical etching conditions (etching chemical solution composition, concentration, etching time) is strictly observed in processing irradiated glasses. The results obtained allow us to conclude that phosphate glasses can be effectively used to detect and identify the superheavy nuclei synthesized at the Factory of Superheavy Elements of the Joint Institute for Nuclear Research (JINR).

The differential cross sections of the B-11(He-3, d)C-12 reaction leading to formation of the 0(+) ground state and the 15.11-MeV 1(+), 16.57-MeV 2(-), and 17.23-MeV 1(-) excited states of C-12 are measured at E-lab = 25 MeV. The analysis of the data is carried out within the coupled-reaction-channels method for the direct proton transfer to the bound and unbound states. The rms radii of the last proton in all states studied are determined. A comparison of the rms radii of the B-12, C-12, and N-12 nuclei in the isobaric analog states (IASs) with isospin T = 1 determined by different methods allows us to arrive at a conclusion that these nuclei in the 1(-) excited states at E-x = 2.62, 17.23, and 1.80 MeV, respectively, possess one-nucleon (neutron or proton) halo structure. The enlarged radii and a large probability of the last neutron to be outside of the range of the interaction potential are also found for the 2(-) states of B-12, C-12, and N-12 at E-x = 1.67, 16.57, and 1.19 MeV, respectively. These IASs also can be regarded as candidates for states with one-nucleon (neutron or proton) halo.

Two independent methods: Asymptotic Normalization Coefficients (ANC) and Modified Diffraction Model (MDM) were applied to new and existing experimental data to search for states with enhanced radii in isobaric analogue states (IAS) of 12 B and 12 N. The ANC analysis of the 11 B(d,p) 12 B reaction at E d = 21.5 MeV has confirmed neutron halo existence for two states of 12 B: 2 − , 1.67 MeV and 1 − , 2.62 MeV [1]. Some new results were obtained for higher excited states: halo-like states were observed for 0 + , 2.72 MeV and 3 − , 3.39 MeV states. It should be mentioned that the last one is unbound state, which is 19 keV above the neutron emission threshold and in both states last neutron has a non-zero orbital momentum (l n =1 and l n =2 correspondingly). We propose to use MDM to study isobaric analogue states of 12 B in the mirror 12 N nucleus and apply it to analyze the ( 3 He,t) reaction data. The existing in the literature data are not completed enough to make definite conclusion about halo in the 2 − and 1 − states of 12 N. This fact simulated us to carry out a new experiment on the 12 C( 3 He,t) 12 N reaction at the end of 2018. The measurements were conducted at the University of Jyväskylä (Finland) using the K130 cyclotron to produce a 3 He beam at E( 3 He)=40 MeV. The differential cross sections of the 12 C( 3 He,t) 12 N reaction were measured in the c.m. angular range 8°–70°. Preliminary results for angular distributions are obtained. MDM analysis of preliminary ( 3 He,t) experimental data is done.

The differential cross sections for the 12C(3He, t)12N reaction leading to formation of the 1+ (ground state), 2+ (0.96 MeV), 2− (1.19 MeV), and 1− (1.80 MeV) states of 12N are measured at E(3He) = 40 MeV. The analysis of the data is carried out within the modified diffraction model and distorted wave Born approximation. Increased rms radii have been obtained for the ground, 2− (1.19 MeV), and 1− (1.80 MeV) states. We revealed that 12B, 12N, and 12C in the isobaric analogue states with T = 1, and spin-parities 2− and 1− have increased radii and exhibit properties of neutron and proton halo states.

The experiment was done to study B-11(He-3, d)C-12 reaction with energy E(He-3)=25 MeV. The aim of the experiment is to determine the properties of C-12 states at high excitation energies and in particular to verify which of the conflicting spin-parity assignments of the 13.35 MeV state (2(-) or 4(-)) should be assigned. Behavior of the experimental angular distribution and also the DWBA calculation correspond to spin parity 4(-) for 13.35 MeV state.

The experiment was done to study 11 B( 3 He, d) 12 C reaction with energy E( 3 He)=25 MeV. The aim of the experiment is to determine the properties of 12 C states at high excitation energies and in particular to verify which of the conflicting spin-parity assignments of the 13.35 MeV state (2 − or 4 − ) should be assigned. Behavior of the experimental angular distribution and also the DWBA calculation correspond to spin parity 4 − for 13.35 MeV state.

An experiment was done to search for states with a neutron halo in B-12. The measurements were carried out at the cyclotron of the University of Jyvaskyla (Finland) using Large Scattering Chamber (LSC). The idea of the work was to search for two states with the expected neutron halo, 1(-) and 2(-). Differential cross sections with excitation of B-12 states, including abovementioned states, were observed. The preliminary calculations on halo radii by the method of asymptotic normalization coefficients for the 2(-) and 1(-) states which are in a discrete spectrum gave following values: 5.6 fm and 7.4 fm, which is much larger than the radius of the valence neutron in the ground state. But strictly the presence of a neutron halo can be confirmed only for 1(-) state. The 2(-) state can be considered only as candidate for halo. An unexpected result was obtained for the 3(-), 3.39 MeV state, which is in continuum 19 keV above the decay threshold B-12 -> B-11 + n, preliminary estimation for its halo radius is similar to 6.5 fm. This indicates that the halo can be present in this state as well. But strict conditions for neutron halo are not fulfilled in the same way as for 2(-) state. Until now, the neutron halo in unbound states has been observed only for the members of the rotational bands.

GaAs Schottky barrier detectors for α particle spectrometry have been tested. Detectors had an input window area of 80 mm2 and a working barrier layer thickness of 40–50 μm. The energy resolution (FWHM) measured on 5.499 MeV α line of 238Pu source amounted to 17.5 keV at a generator peak width of 7.8 keV. In the measurements on a 226Ra source, detectors showed linear response and nearly 100% charge collection efficiency at reverse bias above 65 V for all energies of α particles emitted from the source. Tests for thermal stability showed that the proposed detectors can be used in alpha-spectrometry of radionuclides at temperatures up to 120°C.

AbstractGaAs Schottky barrier detectors for α particle spectrometry have been tested. Detectors had an input window area of 80 mm^2 and a working barrier layer thickness of 40–50 μm. The energy resolution (FWHM) measured on 5.499 MeV α line of ^238Pu source amounted to 17.5 keV at a generator peak width of 7.8 keV. In the measurements on a ^226Ra source, detectors showed linear response and nearly 100% charge collection efficiency at reverse bias above 65 V for all energies of α particles emitted from the source. Tests for thermal stability showed that the proposed detectors can be used in alpha-spectrometry of radionuclides at temperatures up to 120°C.

An experiment was done to search for states with a neutron halo in 12B. The measurements were carried out at the cyclotron of the University of Jyvaskyla (Finland) using Large Scattering Chamber (LSC). The idea of the work was to search for two states with the expected neutron halo, 1 ̄ and 2 ̄. Differential cross sections with excitation of 12B states, including abovementioned states, were observed. The preliminary calculations on halo radii by the method of asymptotic normalization coefficients for the 2 ̄ and 1 ̄ states which are in a discrete spectrum gave following values: 5.6 fm and 7.4 fm, which is much larger than the radius of the valence neutron in the ground state. But strictly the presence of a neutron halo can be confirmed only for 1 ̄ state. The 2 ̄ state can be considered only as candidate for halo. An unexpected result was obtained for the 3 ̄, 3.39 MeV state, which is in continuum 19 keV above the decay threshold 12B → 11B + n, preliminary estimation for its halo radius is ∼ 6.5 fm. This indicates that the halo can be present in this state as well. But strict conditions for neutron halo are not fulfilled in the same way as for 2 ̄ state. Until now, the neutron halo in unbound states has been observed only for the members of the rotational bands.

We present the results of measurements and analysis of the differential cross sections of the 11B(d, p)12B reaction leading to formation of the 1+ ground state and the 0.953-MeV 2+, 1.674-MeV 2−, 2.621-MeV 1−, 2.723-MeV 0+, 3.389-MeV 3− excited states of 12B at Ed = 21.5 MeV. The analysis of the data was carried out within the coupled-reaction-channels method for the direct neutron transfer and the Hauser-Feshbach formalism of the statistical compound-nucleus model. We deduced the spectroscopic factors, asymptotic normalization coefficients, and rms radii of the last neutron in all states studied. The existence of the neutron halos in the 1.674-MeV 2− and 2.621-MeV 1− states was found in consistence with the earlier published data. New information about the enlarged rms radii (6.5 fm) of the last neutron in the unbound 3.389-MeV 3− states of 12B was obtained, which may indicate the evidence of the neutron halo with the orbital momentum of the last neutron equal to two.

Differential cross sections of the elastic scattering of protons of intermediate energies by 9B and 10B nuclei are calculated within the Glauber theory. The matrix elements of elastic scattering are derived with a wave function in the three-particle 2αp-model (for 9B) and with an oscillatory wave function (for 10B). The differential cross-sections are calculated with allowance for the triple collisions on 9B nuclei and in the approximation of double collisions on 10B nuclei. The sensitivity of the differential cross-section to the 9B nucleus structure is analyzed. The differential cross section of 10B at E = 197 MeV is compared to the results from calculations using the distorted wave method.

Differential cross-sections of the elastic and inelastic 13C + α scattering were measured at E(α) = 90 MeV. The root mean-square radii() of 13C nucleus in the states: 8.86 (1/2−), 3.09 (1/2+) and 9.90 (3/2−) MeV were determined by the Modified diffraction model (MDM). The radii of the first two levels are enhanced compared to that of the ground state of 13C, confirming the suggestion that the 8.86 MeV state is an analogue of the Hoyle state in 12C and the 3.09 MeV state has a neutron halo. Some indications to the abnormally small size of the 9.90 MeV state were obtained.